An anechoic chamber in Minneapolis's Orfield Laboratory holds the Guinness world record for the world's quietest place at -9.4 decibels. As humans can only detect sounds above 0 decibels, the chamber is virtually soundless. The room consists of a mesh floor, walls lined with meter-long sound-proofing wedges, and a meshed ceiling. People inside the chamber can hear their own stomach, heart, or even ears, as the ear makes its own noise when it does not detect sound. Source: Minnesota Public Radio